1. Field of the Invention
The present invention relates to an image reading apparatus for reading information of conveyed original and an image formation apparatus using the same.
2. Description of the Related Art
In a case where an image is read by means of an image reading apparatus, an original of the image has to be in intimate contact with a platen glass at a reading position. For this reason, as shown in FIG. 12, a conventional image reading apparatus has a reading white plate 101 for allowing an original S to be in intimate contact with a platen glass 100 at the reading position.
It has been proposed that in order to securely prevent the original from floating at the reading position, a flexible sheet member 102 is provided upstream of the original reading position in the conveying direction to prevent image reading disturbance so that reading accuracy is improved (Patent document 1: Japanese Patent Application Laid-Open No. 2003-051915).
However, in the case of the above-described structure, since the original is pressed by means of the sheet member 102, the contact surface between the sheet member and the original becomes large. Thus, friction noise produced by the sheet member and the original is likely to be considerable. In a case where pressing force of the original is to be increased in order to improve the reading accuracy, when the number of the sheet member 102 is increased in the original width direction or the width of the sheet member 102 is increased, the friction noise is further likely to be bigger.
In the case of the above-described structure, since the sheet member 102 constantly presses the original, at the moment the rear end of the original passes over the sheet member 102, the load applied to the original is released, so that sometimes load fluctuation occurs. Due to the occurrence of the load fluctuation, reading accuracy of the original image may be deteriorated, or the original may flap to generate noise.